Leuco products from gallic compounds and alkyl-diamido-arylthiosulfonic acids, &amp;c.



rinrTnD sTATns PATENT orrron.

CHARLES DE LA HARPE AND RUDOLF BUROKHARDT, or BAsEL, SWITZER- LAND, ASSIGNORS ToDYnwoRKs FORMERLY L. DURAND, HUGUENIN & 00., OF BASEL, SWITZERLAND.

LEUCO PRODUCTS FROMGALLIC COMPOUNDS AND ALKYL-DIAMIDO-ARYLTHIOSULFONIC ACIDS, &c.

Specification of Letters Patent.

Patented Jan. 29, 1907.

To aZZ whom, itmcty concern:

Be it known that 'we, CHARLES DE LA HARPE and RUDOLF BURCKHARDT, chemists, citizens of the Swiss Republic, and residents of'Basel, Switzerland, have invented new and useful Leuco Condensation Products from Gallic Compounds and Alkyl-Diamido- Arylthiosulfonic'Acids and a Process for the Manufacture of the Same, of which the following is a clear, full, and exact specification.

We have found that new compounds very valuable for dyeing and printing are obtained when alkyl-diamidoarylthiosulfonic acids are caused to react with gallic compoundsas, for instance, gallamic acid, gallic acid, methyl gallate, or gallanilid in water, alcohol, or another suitable medium in presence of alkali and with exclusion of air. The

' condensation occurs gradually with elimination of sulfurous acid as a sulfite and with formation of a leuco compound which may easily be oxidized in air; but its hydrochlorid and other salts are not changed by air. These new leuco compounds constitute in dry state and in the form of salts greenish powders soluble in sulfuric acid with a red coloration, becoming violet-black on addition of an oxidizing agent, and yield by oxidation on chromium-mordanted fibers blue-violet shades fast to light and washing.

Example: Into an autoclave having a valve and a double bottom are introduced four hundred. liters of water, eighteen kilos of gallamic acid, and twenty-five kilos of dimethylp araphenylendiaminthi osulfonic acid.

The autoclave is now closed with the exception of the valve, and then is introduced a solution of caustic soda containing twenty kilos of N aOH whilestirring well; The autoclave is then completely closed and the stirring continued, while the temperature is gradually raised to 45 centigrade. After 36-48 hoursthat is to say, when the condensation is complete the autoclave is allowed to cool, and its contents are allowed to flow into -70 kilos of hydrochloric acid of 21 Baum specific gravity. On addition of common salt the condensation product separates in a greenish mass, which is filtered and dried. 'It is slightly soluble in water. On addition of sodium aceta'te'to its aqueous solution a greenish-gray precipitate separates, while on addition of an alkali in presence of air the solution is immediately colored intensely red-violet. In concentrated sulfuric acid the condensation product dissolves to a red solution, which on addition of water becomes pale violet and on addition of a small quantity of an oxidizing agent violet-black. The condensation product can be fixed on textile fibers with aid of chromium mordants and then yields by oxidation on the fiber, whether by air or by an oxidant, such as potassium bichromate, blue-violet shades which are fast to light and washing. 'In this example there can be substituted for the water and dimethylparaphenylendiaminthiosulfonic acid a solution of the sodium salt of this acid, such as is obtained by the action of a chromate on dimethylparaphenylendiamin and a thiosulfate in presence of zinc chlorid and treating .the product with a solution of sodium carbonate or caustic soda.- Similar condensation products may be obtained by substituting for the gallamic acid in this example an equivalent quantity of gallic acid,

methyl gallate, or gallanilid. Moreover, in the example there may be used twenty-eight kilos of diethylparaphenylendiaminthiosulfonic acid instead of twenty-five kilos of dimethylparaphenylendiaminthiosulfonic acid. Finally, for the twenty kilos of caustic soda of the example may be substituted thirty kilos of calcium hydroxid if the mixture be heated to 60 centigrade.

hat we claim is- 1. The described process for the manufacture of new leuco compounds suitable for dyeing and printing, by reacting with an alkyl-diamidc-arylthiosulfonic acid on a gallic compound, in presence of alkali with exclusion of air.

2. The described process for the manufacture of new leuco compounds suitable for dyeing and printing, by reacting with a dialkylparaphenylendiaminthiosulfonic acid on gallamic acid, in presence of alkali with exclusion of air.

3. As new products the descrlbed leuco compounds suitable for dyeing and printing,

derived from an alkyldiamido-arylthiosulfonic acid and a gallic compound, which constitute in the form of salts and in dry state greenish powders soluble in sulfuric acid with red coloration becoming violet-black on addition of an oxidizing agent and yield,

by oxidation on chromium-inordanted fibers, blue-violet shades fast to light and washing.

4. As a new article of manufacture the described leuco compound suitable for dyeing and printing derived from a dialkylparaphenylendiaminthiosulfonic acid and gallarnic acid, which constitutes in the form of its hydrochlorid and in dry state a greenish powder slightly soluble in water, yields by oxidation on chromium-mordanted fibers, blue-violet shades fast to light and washing, dissolves in sulfuric acid with red coloration our names in the presence of two subscribing witnesses.

CHARLES DE LA HARPE. RUDOLF BUROKHARDT.

WVitnesses GEO. GIFFORD, AMAND BITTER 

